[Bug testsuite/70699] Add dot-file scan to pr70161.c test-case

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70699

--- Comment #2 from vries at gcc dot gnu.org ---
pinged: https://gcc.gnu.org/ml/gcc-patches/2016-04/msg00783.html